On-therapy HBsAg kinetics can predict HBsAg loss after nucleos(t)ide analogues interruption in HBeAg-negative patients. The cup is half full and half empty.

BACKGROUND: Nucleos(t)ide analogues withdrawal may improve HBsAg loss rates. However, conditions to select patients are not well established. AIMS: to evaluate the impact of HBsAg kinetics before treatment interruption on post-treatment response. METHODS: Longitudinal, ambispective study in non-cirrhotic chronic hepatitis B HBeAg-negative patients, analysing on-treatment and post-treatment HBsAg kinetics. On-treatment HBsAg kinetics diagnostic accuracy (AUROC) to identify HBsAg loss was evaluated. RESULTS: 52 HBeAg-negative patients stopped treatment after 8.2 years, and 6 (11.5%) achieved HBsAg loss one year after withdrawal. Multivariate analysis showed that on-treatment HBsAg kinetics was related to HBsAg loss (OR=0.10; 95%CI=0.016-0.632; p = 0.014) with a high diagnostic accuracy (AUROC=0.935). A significant HBsAg decline ≥1 log10 IU/mL showed a positive and negative predictive value of 50% and of 97.6%, respectively. After treatment interruption, HBsAg decline speed (log10 IU/mL/year) accelerated in patients treated >6 years (from -0.06 to -0.20, p<0.05) and remained stable in treated <6 years (from -0.12 to -0.12 p=ns). CONCLUSIONS: On-treatment HBsAg kinetics can predict post-treatment HBsAg loss rate. Half of patients with a significant HBsAg decline can eliminate HBsAg the first year after withdrawal. Post-treatment HBsAg decline is faster not only in patients who lost the HBsAg but also in those who remain HBsAg-positive.